Social Reader apps are probably best known for their automatic, or “frictionless,” sharing. The feature was both loathed and effective in a brute-force kind of way: It drove millions of new readers to content produced by publications venerable and new. The Guardian, out of London, was one of the early adopters of the tech, which it now says was used by at least “12 million Facebook users.”

Facebook has taken steps to discourage automatic sharing, making auto-shared stories far less visible in users’ timelines. But the controversy around and ensuing changes to frictionless sharing on Facebook distracted from social readers’ second-most important feature: While they’re great at showing users content from websites, they do so entirely on Facebook.

Many of those 12 million people never had to leave Facebook to read the Guardian (or The Washington Post, or the Huffington Post), so while they were technically new readers, they often weren’t new visitors. The WaPo app still works this way — here’s what you see when you click a story:

Publications have cooled somewhat on social readers apps as they’ve become less effective at gathering users. But the Guardian has announced that it’s fundamentally changing how its social reader works, and it’s taking control of its content back from Facebook. Group Product Manager Anthony Sullivan writes, “from Monday 17 December we will begin directing users who click on a Guardian link within Facebook straight to our website to view articles, so over time all users will no longer be shown the content on a page within Facebook.”

He explains the decision to initially serve social reader stores on Facebook as part of an “experiment,” and says that the paper’s website will integrate more Facebook widgets in the future.

But the subtext is clear. The Guardian is no longer comfortable with the idea of existing merely as an app within Facebook; it would rather let Facebook behave like an app on its own site. It wants to own its users, not borrow them from Facebook.

It has become clear that Facebook — and increasingly Twitter — would prefer its users never have to leave. Content providers are rightly beginning to wonder if that’s in their best interest.